Short-nosed unicornfish (Description – habitats – feeding habits – reproduction)- Video


The video was taken in the Sea World, San Diego, USA

Review: Abdel Rahman El Gamal (Founder of the website and video channel)

General: The short-nosed unicornfish (Naso brevirostris) which belongs to the family Acanthuridae has other names including spotted unicornfish, and brown unicornfish. In general, it is a very peaceful fish whether in the wild or in captivity in tanks. The species is not targeted in multi-species fisheries and hence, the conservation category is “least concern” according to the IUCN red list. The short-nosed unicornfish can live up to 25 years.

Description: Unicorn fish has elongate and oval body with a short snout. Their name comes from the horn which star growing at a particular age/size (15-25 cm) and turns into a pronounced horn on the front of their heads in their adulthood. The species has also two sharp spines located on each side of its body, next to the caudal fin. These are used for self-defense. The maximum length of the species has been reported to be 60 cm. Unicorns are very active swimmers.

Geographic range and habitats: The short-nosed unicornfish inhabits variety of world tropical waters. The species occurs on coral reefs and rocky shores at various depths which could range from 0 – 45 meters (usually 5-30 m) for adults. Juveniles inhabit sheltered habitats with seagrass beds at depths which can reach 20-meters.

Feeding habits: Juveniles and sub-adults of unicorn fish feed on benthic and filamentous algae; adults feed primarily on zooplankton. It is believed that the change in food habits may be associated with the development of the long horn which would inhibit grazing on algae except on the boarders of reefs as horns do not get in the way. They can feed also on pelagic fish larvae.

In aquariums, unicorns are grown on aquarium foods which include live adult brine shrimp, larger shrimps, live marine algae, boiled broccoli and variety of worms.

Reproduction: Unicorn fish are of separate sexes that reach their sexual maturation at about 25-cm length. It is believed that the species spawn in pairs and may form spawning aggregations in the spawning grounds. The mating pair swim along together, touch bellies and then the female eject her heir pelagic eggs that hatch –after fertilization by male’s sperm- into relatively large larvae which stays in the pelagic environment for about 90 days before moving to more appropriate environments.

References: Wikipedia, Discover Life, Wakatobi, Encyclopedia of Life



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